INHIBITORY EFFECT OF ALPHA-TOCOPHEROL ON METHEMOGLOBIN FORMATION BY NITRIC-OXIDE IN NORMAL AND ACATALASEMIC MOUSE HEMOLYSATES

The inhibitory effect of alpha-tocopherol on methemoglobin formation i n normal and acatalasemic mice was studied by exposing their hemolysat es to nitric oxide. Methemoglobin formation in normal and acatalasemic mouse hemolysates exposed to nitric oxide were significantly inhibite d by the addition of alpha-tocopherol at final concentrations ranging from 1.2 to 5.8 mM. Negative correlations were observed between the lo garithm of alpha-tocopherol concentration and the methemoglobin format ion. The formation of methemoglobin in acatalasemic mouse hemolysates was greater than that in normal mouse hemolysates with or without adde d alpha-tocopherol. The methemoglobin formation in acatalasemic mice w as also significantly inhibited by addition of more than 500 units/ml of catalase, and the methemoglobin formation in normal and acatalasemi c mice was also inhibited with sodium diethyldithiocarbamate at a fina l concentration of 1 M.